Many activities depend on the collection of large and complex bodies of data. The data is processed and results of the processing are used to guide the activities. The collection of data in connection with many of these activities is itself complex and expensive. In one example, undersea oil drilling requires the collection of data to identify likely locations for oil deposits, because undersea drilling is enormously expensive. Energy concerns collect seismic data, which is then processed to identify locations of prospective deposits. One common data collection method is the towing of a hydrophone array by a ship. A ship may tow a two-dimensional array of hydrophones spaced approximately 25 meters apart on 1 to 16 trailed streamers. Every 15 seconds or so, an air cannon is fired into the water, creating an acoustic wave that propagates through the water and into the earth. Reflections from various surface and subsurface boundaries cause echoes that reflect back, and the echoes captured by each hydrophone in the array are recorded. The recording of a single hydrophone over time appears as a trace, and the collection of traces for a single firing of a cannon is called a common shot gather, or shot. As a ship moves, a large set of spatially overlapping shots is recorded. Depending on the survey region to be imaged, such data collection may take a month or more and is designed to achieve maximal coverage of an area to be imaged. Usually a ship passes back and forth over an area at a slow speed, performing tens of thousands of shots. A data collection ship may cost on the order of $1 million per day.